A sabot is a commonly used ordnance term to define a sleeve or carrier to center a sub-caliber projectile in a gun bore. Upon firing, the sabot generally separates from the projectile after the assembly leaves the gun muzzle. Sabots may be used with both conical-shaped bullets as well as traditional lead ball bullets. When used with a firearm with a rifled barrel, the sabot may be used to impart rotation to the projectile as it travels down the gun barrel after firing. In particular, the sabot is typically formed to have a diameter the same as the grooved diameter of the rifled barrel so that the sabot is pressed into the rifling after firing.
Some of the problems encountered in providing a sabot bullet for shotguns include the fact that there exist large variations in shotgun bore diameters, configurations and interior taper or choke. The shellcase diameter will normally exceed the bore diameter or the choke, and therefore any load component, e.g., projectile, wadding, sabot, etc., must either be of a lesser diameter than the minimum choke diameter, or be formed of a material which may compress or otherwise be capable of deformable flow to pass through the choke.
What is needed is a sabot capable of providing safe firearm operation with a low dispersion in an efficient energy transfer manner without damaging the gun barrel.